Abstract
BACKGROUND AND OBJECTIVES: Agenesis of the corpus callosum (ACC) is a common congenital brain malformation. Early development in ACC remains unexamined, despite the increased likelihood for developmental delays and autistic behaviors. This study compares adaptive functioning in infants/toddlers with isolated ACC to children with other neurodevelopmental conditions and typical development. METHODS: Parents of children with ACC completed the Vineland Adaptive Behavior Scale Interview at 6, 12, 18, and 24 months as part of a prospective longitudinal study. Comparison groups included children with fragile X, Down syndrome, high familial likelihood of autism spectrum disorder (both with and without autism spectrum diagnosis), and typical development (total n = 957; total assessments = 2676). RESULTS: By 24 months, 29% of children with ACC were delayed in at least 1 domain. Linear mixed effect models showed significant group × time point interactions in all domains. Post-hoc comparisons revealed the ACC group had poorer performance in communication by 6, motor by 12, and daily living by 18 months but equivalent socialization compared with typically developing children; stronger skills across most domains and time points compared with genetic groups; and equivalent communication, stronger socialization, and weaker motor skills compared with the autism group. CONCLUSIONS: Although there is significant variability, on average, ACC compromises communication skills by 6 months, with reduced motor and daily living skills by 12 and 18 months, respectively. Multipronged intervention programs are needed for ACC beginning early in the first year of life, possibly leveraging early strengths in social skills.